And how was "the militia" defined by the Founding Fathers? According to George Mason, the "militia" is every one not associated with the government.
As Jordon Peterson said, words are defined and understood in the context of their usage.
In the US Constitution, there is no other entity which has the specific mission to repel invasion. That is not my opinion. That is FACT.
The problem is, we Americans have gotten our heads so far up our asses, we don’t know how to think anymore. Gov Abbott and every other governor always had the power and authority to deal with invasion. It doesn’t. need the federal government or SCOTUS to do anything.